Excellent book. Watch the movie "Breach" before you read this book. If you have the time, read up on Aldrich Ames. There are a few books on the subject. Among the best books this reader has experienced is "Confessions of a Spy" The book details the actions of Aldrich Ames, and then "Circle of Treason" which details the efforts of the team that exposed Ames. It sort of works in conjunction with "Spy", because it documents several events and actions on behalf of a joint effort by the FBI and CIA to catch Ames and, later on, Hanssen. VERY INTERESTING WORKS BY THE AUTHORS. Excellent sources, and post-investigation history. Do it, BUY THESE BOOKS. I was not let down, in regards to the structure in the writing of these books, and neither will you.